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M H Nasr-Esfahani

Publications and source records attributed to M H Nasr-Esfahani.

14 recordsLinked to original sources
PubMed2006

Can sperm protamine deficiency induce sperm premature chromosomal condensation?

Sperm premature chromatin condensation (PCC) has been considered as the second cause of failed fertilization post-intracytoplasmic sperm injection (post-ICSI). Cytoplasmic factors, including oocyte cytoplasmic immaturity have been suggested to induce PCC sperm. However, recent studies suggest that sperm chromatin anomaly might also lead to PCC sperm. During this study, human sperm from infertile patients with protamine deficiency or with adequate amount of protamine assessed by chromomycin A3 were injected into metaphase II mouse oocyte, treated with colcemid. Chromatin analysis was carried out on the injected oocyte. The results of this study show that contrary to the percentage of intact sperm, percentage of PCC sperm was significantly higher in oocytes injected with protamine deficient sperm (36.43 +/- 4.46) compared to oocytes injected with sperm with an adequate amount of protamine (11.99 +/- 3.54, P < 0.001). A significant correlation was also observed between percentage of PCC sperm and protamine deficiency (r = 0.46, P = 0.004). Therefore, it can be suggested that oocytes injected with protamine deficient sperm have a higher chance of forming PCC sperm and may result in failed fertilization post-ICSI.

Animals↗
PubMed2004

Effect of protamine-2 deficiency on ICSI outcome.

During spermiogenesis, histones are replaced by protamines (P1 and P2), resulting in sperm chromatin condensation followed by a halt to gene expression in haploid spermatids and spermatozoa. As a consequence, protamine deficiency and aberrant P1/P2 ratio have a profound effect on both fertilization and embryo development. However, reports on the effect of the P1/P2 ratio on fertilization and embryo development after intracytoplasmic sperm injection (ICSI) are contradictory between human and animal studies. The question that still remains to be elucidated is which type of protamine deficiency is most common among protamine deficient samples. The present study has a direct bearing on this issue investigating the correlation of the P1/P2 ratio with protamine deficiency, fertilization, embryo quality and embryo development in ICSI patients. This study was carried out on 71 patients. Chromomycin A3 (CMA3) staining was used to determine protamine deficiency. Since this procedure does not indicate the type of protamine deficiency, the P1/P2 ratio was evaluated by nuclear protein extraction, acetic acid urea polyacrylamide gel electrophoresis and analysis of protein bands with software. Polyclonal anti-P1 and anti-P2 antibodies were used to confirm P1 and P2 presence. Results show a negative significant correlation of fertilization rate with protamine deficiency and P1/P2 ratio. No significant correlation was observed between protamine deficiency and P1/P2 ratio. Therefore, it can be concluded that altered P1/P2 ratio effects fertilization rate and embryo quality which subsequently may affect implantation and pregnancy outcome.

Adult↗
PubMed2004

Relationship between protamine deficiency with fertilization rate and incidence of sperm premature chromosomal condensation post-ICSI.

After aneuploidy, sperm premature chromatin condensation (PCC) is the next prevalent cause of fertilization failure. Therefore the aim of this study was to evaluate the effect of sperm protamine deficiency on sperm PCC formation post-ICSI. Chromatin analysis was carried out on failed fertilized oocytes post-ICSI and incidences of sperm PCC were evaluated and the results were compared with the extent of protamine deficiency assessed by chromomycin A3. The results show that incidence of sperm PCC was significantly different in failed fertilized oocytes injected from semen samples with greater or less than 30% CMA3 positivity (P = 0.04). However, except for fertilization rate (P < 0.001), the mean number of MII, MI and germinal vesicles oocytes and percentage normal sperm were not significantly different between the two groups (P > 0.05). A significant correlation was observed between sperm protamine deficiency with fertilization rate. Hence sperm protamine deficiency affects fertilization rate and possibly prones sperm to PCC post-ICSI.

Adult↗
PubMed2003

Effect of human sperm chromatin anomalies on fertilization outcome post-ICSI.

The aim of this study was to evaluate the effect of sperm chromatin anomalies on fertilization outcome post-intracytoplasmic sperm injection (ICSI). Therefore, along with semen parameters, Chromomycin A3 (CMA3) staining for protamine deficiency, aniline blue staining for excessive histones, SDS for sperm chromatin stability and SDS + EDTA for the ability of sperm to undergo decondensation were carried out on 55 semen samples from patients referred to the Isfahan Fertility and Infertility Center for ICSI. The results showed that among the aforementioned tests and semen parameters only CMA3 showed a significant correlation with fertilization outcome post-ICSI. Patients were also grouped according to CMA3 level of <30% or >30% or fertilization rate of <50% or >50%. The results show that the mean percentage fertilization and mean percentage of CMA3 positivity is different in both groups, respectively. The area under receiver operator characteristics curve shows that CMA3 is a highly sensitive and specific test for prediction of fertilization outcome post-ICSI. In conclusion, that sperm protamine deficiency has profound effect on fertilization failure in ICSI.

Chromatin↗
PubMed2001

Relation between different human sperm nuclear maturity tests and in vitro fertilization.

PURPOSE: To consider the relationship between different sperm nuclear maturity tests and in vitro fertilization (IVF) rate, in order to select the most sensitive, specific, and independent factor(s) for prediction of in vitro fertilization. METHODS: Infertile couples (101) were randomly selected from IVF candidates referred to Isfahan Fertility and Infertility center. Semen samples were collected on the day of oocyte recovery. Following routine semen analysis, major portion of the semen was prepared for routine IVF insemination and the remaining was used for following sperm nuclear maturity tests: chromomycin A3 (CMA3), aniline blue, sodium dodecyl sulphate (SDS) test, and acridine orange test with or without heat shock (87 degrees C, 5 min). Sperms (200) were evaluated for each test. The results were recorded and analyzed for their correlation to fertilization rate, using correlation coefficient, logistic regression analysis, student t-test, and receiver operating characteristics (ROC) curve. RESULTS: Among these tests, aniline blue and CMA3, and semen parameters, sperm morphology, and sperm motility showed a significant correlation with fertilization rate. Using logistic regression analysis, sperm morphology and CMA3 were the only independent factors related to in vitro fertilization. ROC curves showed that among above tests, CMA3 is the most specific and sensitive for sperm nuclear maturity. CONCLUSION: Among CMA3, aniline blue, SDS test, and acridine orange, CMA3 was the most sensitive and specific test that can be used along with routine semen analysis for more precise prediction of fertilization rate.

Acridine Orange↗
PubMed2000

Chromomycin A3 staining as a useful tool for evaluation of male fertility.

PURPOSE: Our purpose was to investigate the association between percentage chromomycin A3 (CMA3) positivity of spermatozoa with some sperm parameters and in vitro fertilization rate. METHODS: Spermatozoa were collected from 139 men, washed in PBS, fixed in methanol/glacial acetic acid (3:1), and then spread on slides. CMA3 positivity is expressed as the percentage in 200 spermatozoa. RESULTS: Percentage of CMA3 positivity showed not only a negative correlation with fertilization rate but also a significant difference between fertilizing and nonfertilizing patients. Moreover, percentage of CMA3-positive spermatozoa showed a negative correlation with count and percentage motility and a positive correlation with percentage of abnormal morphology. Percentage of CMA3 positivity also had a positive correlation with some abnormalities of head such as amorphous and macrocephaly. Ultrastructural study showed chromatin unpackaging in high CMA3-positive semen samples in comparison with low CMA3-positive semen samples. CONCLUSION: There is a close relationship among fertilization rate, sperm parameters, and CMA3 positivity and CMA3 could be considered as a useful tool for evaluation of male fertility prior to infertility treatment.

Chromatin↗
PubMed1994

Radical solutions and cultural problems: could free oxygen radicals be responsible for the impaired development of preimplantation mammalian embryos in vitro?

A major obstacle to the study of mammalian development, and to the practical application of knowledge gained from it in the clinic during therapeutic in vitro fertilisation and embryo transfer (IVF-ET), is the propensity of embryos to become retarded or arrested during their culture in vitro. The precise developmental cell cycle in which embryos arrest or delay is characteristic for the species and coincides with the earliest period of embryonic gene expression. Much evidence reviewed here implicates free oxygen radicals (FORs) in the process of arrest. Thus, studies on the development of mouse preimplantation embryos in vitro have shown that (i) FORs are elevated in vitro, but not in vivo, at the time at which embryos become arrested or delayed, (ii) systems for removing reactive oxygen species to limit the formation of hydroxy radicals are present, although they have not yet been assessed quantitatively and may differ qualitatively from those in adult cells, (iii) metabolic and possibly genetic adaptations to oxidative damage are evident, (iv) published procedures for overcoming in vitro arrest are explicable in terms of FOR-mediated damage or responses and (v) the arrest or delay of most embryos in vitro can be reduced or prevented experimentally by addition of metal chelators to limit hydroxy radical formation and lipid hydroperoxidation.

Animals↗
PubMed1993

A scanning electron microscopic study of the chick chorioallantoic membrane: cell death and the involvement of oxygen free radicals.

Cell death is a normal feature within the chick chorioallantoic membrane, occurring principally between days 10 and 14 of incubation. Samples of chorioallantoic membrane were obtained on days 6, 8, 10, 12 and 14 of incubation, after the creation of artificial air chambers on day 3. These were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) after staining for acid phosphatase activity, and by light microscopy after demonstrating oxygen free radicals with nitro blue tetrazolium. On day 6, small defects in the plasmalemma, approximately 200 nm in diameter, could be seen by SEM. A sequence of events leading to complete destruction of the plasmalemma, with exposure of the nucleus and other cytoplasmic organelles, could be traced, and by day 8 the membrane was a mosaic of healthy cells and others in various stages of degeneration. TEM revealed that acid phosphatase activity was confined to the golgi apparatus and associated vesicles even in advanced stages of degeneration. By comparison, oxygen free radicals were demonstrated in individual cells from day 6 onwards. Application of superoxide dismutase and catalase to the epithelium using a nebuliser spray significantly reduced the amount of cell death seen by scanning microscopy on day 12. It is concluded that oxygen free radicals may mediate cell death in the chorioallantoic membrane.

Acid Phosphatase↗
PubMed1992

Quantitative analysis of cellular glutathione in early preimplantation mouse embryos developing in vivo and in vitro.

The relative levels of reduced glutathione (GSH) have been measured fluorimetrically in individual eggs and early embryos from two mouse strains, one of which shows developmental arrest in vitro. GSH levels fell by approximately 20-25% at fertilization and by approximately 45% by the late 2-cell and early 4-cell stages. No differences were observed between strains or between embryos cultured in vitro or in vivo. Addition of exogenous H2O2 or diethylmaleate depleted GSH. GSH levels were not affected significantly after inhibition of GSH-peroxidase by mercaptosuccinate nor of catalase by aminotriazole. Mercaptosuccinate did not inhibit development but catalase inhibition caused arrest at the 2-cell stage. Addition of exogenous GSH or thioredoxin did not promote development of 'blocking' embryos through the 2-cell block. It is concluded that early embryos lack a mercaptosuccinate sensitive peroxidase activity for removing H2O2, which may be removed by catalase or the glutathione-S-transferase system. It is suggested that GSH may have a role in detoxifying peroxidated lipids. The results are consistent with a role for reactive oxygen species in the 2-cell block.

Amitrole↗
PubMed1992

How does transferrin overcome the in vitro block to development of the mouse preimplantation embryo?

Transferrin promotes development of mouse embryos through the two-cell block in vitro. Uptake of transferrin into blastocysts was shown to occur by both receptor-mediated and nonspecific pathways, but neither pathway was used to a detectable extent by embryos before the eight-cell stage. Conversely, the dialysis of culture medium, non-permissive for development through the two-cell block, against a solution of transferrin rendered it capable of supporting development. It was therefore concluded that transferrin exerts its supportive effect on development in vitro via its chelating effects.

Animals↗
PubMed1992

Effects of glucose, glutamine, ethylenediaminetetraacetic acid and oxygen tension on the concentration of reactive oxygen species and on development of the mouse preimplantation embryo in vitro.

Analysis over the first 48 h of development in vitro from the one-cell stage to the early four-cell stage indicated that (i) ethylenediaminetetraacetic acid (EDTA) exerts the major beneficial effect on culture to the blastocyst stage of F1 and MF1 embryos, (ii) glutamine assists development of MF1, but not F1, embryos to the blastocyst stage and probably functions as part of a metabolic response to oxidative damage to mitochondria and (iii) exposure to glucose at some time during early cleavage is essential for full development to blastocysts. None of the culture conditions examined affected significantly the increase in concentration of reactive oxygen species in late two-cell embryos in vitro, although F1 embryos in vitro often had lower peroxide concentrations than MF1 embryos. A decline in oxygen tension from 20 to 50% had no consistent effect on culture to the blastocyst stage or production of reactive oxygen species. Aminooxyacetate, an inhibitor of transaminase activity, prevented non-blocking embryos from developing beyond G2 of the second cell cycle. It is concluded that the chelation of transitional metals provides the most effective method of overcoming the block to development in vitro.

Animals↗
PubMed1990

Hydrogen peroxide levels in mouse oocytes and early cleavage stage embryos developed in vitro or in vivo.

We describe a fluorimetric method for measuring the level of H2O2 in individual mouse oocytes and early embryos. Levels of H2O2 are low but detectable in unfertilized oocytes recovered freshly from the female reproductive tract. The levels in early cleaving embryos (1-cell to 8-cell stages) immediately after recovery from the female tract seem to be slightly higher the later the stage examined. However, when embryos are cultured in vitro from the 1-cell or early 2-cell stage, H2O2 levels rise when the embryos reach the mid-2-cell stage and remain elevated until they enter the early 4-cell stage. No equivalent elevation of H2O2 is seen during the transition from 1-cell to 2-cell or from 4-cell to 8-cell stages. Embryos that are able to develop successfully in vitro, as well as those that show a developmental block at the 2-cell stage on culture in vitro, both show this rise in H2O2 levels after in vitro culture. The relationship between the rise in H2O2 and the '2-cell block' to development is discussed.

Animals↗
PubMed1989

The effect of macrophage stimulation on the uptake of acetylated low-density lipoproteins.

The rapid uptake of modified low-density lipoproteins (LDL) by macrophages in the arterial wall may lead to their conversion into lipid-laded foam cells in atherosclerotic lesions. We have therefore investigated the effects of macrophage stimulation on their rate of uptake of modified LDL. The uptake of 125I-labelled acetyl-LDL by mouse resident peritoneal macrophages was reduced by about 60-85% by zymosan (250 micrograms/ml), by 25-45% by lipopolysaccharide (0.1-1 mg/ml) and 50-60% by phorbol myristate acetate (100 nM). The inhibition was dose-dependent and was observed at the earliest times studied (about 1 h). Binding studies at 0 degrees C showed that all three stimulating agents decreased the number of cell-surface receptors for acetyl-LDL. If macrophages are stimulated in atherosclerotic lesions, this may therefore be beneficial in that it may decrease their numbers of receptors for modified LDL, although it may be harmful in other ways in that stimulated macrophages may release factors that damage the arterial wall.

Animals↗